Our long term goal is to develop an effective vaccine to treat malignant melanoma. A critical element in this effort is to identify immune effector mechanisms which mediate the clinical benefits of vaccine treatment. While it is known that melanoma vaccines can stimulate humoral and/or cellular host immune responses against melanoma, the relative importance of these responses in mediating resistance to melanoma is not known. We propose to conduct a tightly focused study to analyze the immunological consequences of vaccine treatment, and to define effector immune responses which correlate with improved clinical outcome. The study will be conducted in the context of, and to complement, an ongoing randomized clinical trial of melanoma vaccine immunotherapy. The proposal has two principal aims: 1) To determime the effects of melanoma vaccine immunization on selected parameters of host T and B cell immune responses to allogeneic and autologous melanoma. Selected parameters of cellular and humoral immune responses to vaccine immunization will be measured prior to, and at fixed intervals following, vaccine treatment. 2) To identify vaccine induced antitumor T or B cell immune responses which are important in mediating clinically effective antitumor immunity; as evidenced by correlations with clinical outcome of disease. Successful completion of this work will provide basic immunological information required for the rational development of effective vaccines for the primary and secondary prevention of malignant melanoma.